The present invention relates generally to agricultural aero-applicator devices for widely broadcasting agri-chemicals. More particularly, the present invention is related to an aerodynamically shaped spreader adapted to uniformly apply agri-chemicals with a minimum of aerodynamic drag and interference.
In the prior art it is well known to dispense various agri-chemicals from the air. However, as will be readily appreciated by those skilled in the art, it is desirable to distribute such chemicals, which may include insecticides, herbicides, or the like, substantially uniformly below the aeroplane so as to properly treat the crop without "overdosing" or missing any particular row or column. Therefore a variety of prior art aero-applicator devices have been employed to distribute agri-chemicals.
For example, U.S. Pat. No. 3,777,978 discloses a spreader device consisting of a receptacle disposed beneath a conventional hopper for broadcasting agri-chemicals through a diffusing unit including a plurality of internal vanes. The most relevant prior art known to me is disclosed in U.S. Pat. No. 3,476,337 issued to W. D. Cornett, Jr., on Nov. 4, 1969. This unit includes a spreader device having a divergent body in which an input throat receives agri-chemicals to be subsequently distributed. A plurality of internal vanes extending between the diverging top and bottom of the unit broadcast in what is represented as being a substantially uniform pattern.
Other related devices are seen in U.S. Pat. Nos. 4,412,654, 3,533,582, and 2,772,061. Less related prior art is seen in U.S. Pat. Nos. 1,851,406 and 2,220,082.
However, depending upon a wide variety of conditions encountered in actual agri-chemical spray plane use, the apparatus must be capable of adjustment so as to facilitate homogenous product distribution. In other words, once the conventional hopper of the aeroplane is employed to input the agri-chemical or the like to be dispensed, product passage through the spreader must be substantially homogenous, and uniform diffusion is necessary. These characteristics are increasingly difficult to maintain when varying conditions are encountered by the applicator.
One very important factor to be considered, as will be appreciated by those skilled in flying, of course relates to the direction of prop rotation. Most single engine planes have clockwise prop rotation. Clockwise rotation will produce opposite effects upon the outputted spray than will counterclockwise rotation. In other words, prop rotation establishes a non-symmetrical air flow behind and underneath the aircraft. With normal spreaders it is difficult, if not impossible, for the aviator to compensate for uneven wind effects caused by prop rotation.
Other problems may be caused by prop (P)-Factor, aircraft design, or the presence of aircraft component parts such as landing gears, wing struts, oil coolers and the like. Such factors effect the flow of air around any model or design aircraft and create air turbulence which can greatly affect the distribution of material distributed from spreader devices.
Hence, to provide a reliable spreader unit of versatile characteristics, I have found it necessary to provide a variety of adjustments to the unit to vary the output to operationally mate to the individual design of the aircraft. Moreover, in order to avoid "dead zones" within the fluid flow region set up within the vanes of the spreader, I have provided a system for laterally injecting mixing air at the periphery of the device so as to insure substantially homogenous output density, and a uniform output pattern. As a result my spreader may be adjusted to insure uniform application of an agri-chemical upon a target field without the disadvantages characteristic of prior art devices.